From what I remember, we were talking about the Kreb’s Cycle, RER, RQ, along with the different metabolic pathways.
It revolves around the intensity percentages and duration, she was saying that yea you may burn more fat by percentage at lower exercise intensities, but you’ll burn more calories at higher intensities. And in doing that, where the body drew energy from was predominantly carbs at high intensity.
I think the saying referred to that burning more calories per exercise session was the overall goal to slim down faster/more efficiently rather than burning small amounts of fat during exercise.
Have you exercised at high intensities before keto and since you’ve been fat adapted? I’m curious to know if there was a change in how long you were able to sustain a high intensity under both conditions. I’ve not exercised like that, just Couch 2 5K sessions. We know that endurance athletes don’t hit a wall and bonk like sugar burners during marathons, but that’s sub-maximal.